An Irish court has thrown out a case taken against the Welsh government over an alleged breach of copyright in relation to photographs of poet Dylan Thomas and his wife, Caitlin, used in a campaign by the Welsh tourist board, which shows them playing croquet and strolling through the countryside as newlyweds.

In a second hearing, also in Dublin high court, a libel case was dismissed against the 93-year-old widow of the man who took the photographs in the 1930s.

The Thomas marriage is famous for its boisterousness and drunken rows, portrayed in the John Maybury film The Edge of Love. But it was to the couple’s more harmonious early years that Visit Wales turned for a campaign to celebrate the the centenary of the poet’s birth in 2014.

In the ruling on the accusation against the Welsh government, the judge said if the case was to proceed, it should be heard in a court in Wales or England. Price had argued he had the right to sue in an Irish court because he now lived in Ireland.

The photographs were among eight taken by the Thomases’ friend and fellow poet Vernon Watkins that had remained in the possession of his widow, Gwen, until she sold them in 2011 to the former BBC journalist Haydn Price. One was titled Just Married and features Thomas and Caitlin shortly after their wedding in 1937; the second was called Pennard and showed the couple playing croquet.

Price, the owner of Pablo Star Media, paid Gwen Watkins £1,000 (€1,330) for the photographs in 2011. Price has since launched legal actions in Ireland, the Netherlands and the US over alleged breaches of copyright. In November 2015, Price was awarded €1,500 by Dublin district court after it found the Scottish theatre company Tron had used one of the photos without permission on its Storify social media page.

A year earlier, in 2014, he sued Barbara Epler, the owner of New Directions Publishing in New York, for using the same photo – of Thomas playing croquet – on a book cover. Price’s allegations of libel against Gwen Watkins, for which he was seeking €75,000 in damages, centred on a letter she wrote to Epler, in which she referred to “that bad man Haydn Price whose actions have blackened my otherwise serene old age”.

In the letter, which was read to the court, Watkins stated that Mr Price “had plotted with someone I had thought a friend to visit my house. He stayed for seven hours. I could not get him to leave … I was apprehensive because I sensed that he was a violent and unstable man and I was alone in the house with him. He got such a bad name that he eventually left the UK.”

Price, who said he had a masters in copyright law, denied that anything in her letter was true and outlined a file of emails he and Watkins had exchanged that, he said, proved their relationship was friendly and above board.

But in Dublin high court on Friday, Mr Justice Groarke said Price had not given the court any proof that Mrs Watkins’s letter had been published to anyone and dismissed his claim.

In the earlier case against Tron theatre company, Price was reported by the Irish Times to have said he wanted to protect the integrity of the croquet image as he wanted to “develop a whole brand around the image”, including stationery and notebooks, alongside other “studenty, middle-class giftware”.